This application claims the priority of Korean Patent Application No. 2003-8762, filed on Feb. 12, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a method of manufacturing an electric field device, and more particularly, to a method of manufacturing an electric field device that can uniformly emit light having a high brightness.
2. Description of the Related Art
Carbon nanotubes (CNTs) have a small diameter and a high aspect ratio of diameter to length and thus can emit electrons even at a low voltage. Since the CNTs have excellent electron emission characteristics and are chemically and physically durable, extensive studies have been performed on the physical properties and applicability thereof. Meanwhile, spindt-type field emission devices use metal micro tips as electron emitters. The micro tips have a problem that the life span is reduced under atmospheric gas and a non-uniform electric field during emission of electrons. A low work function of an emitter is required in order to lower a driving voltage for emitting electrons, but conventional micro tips are reaching the technical limit. To overcome these problems, field emission arrays (FEAs) using the foregoing CNTs as electron emitting sources have been developed because the CNTs have a high aspect ratio and are highly durable and conductive.
U.S. Pat. No. 6,440,761 to Choi discloses an FEA using a paste mixture of electron emission materials and a method of fabricating the same. U.S. Pat. No. 6,339,281 to Lee et al. discloses an FEA and a method of fabricating the same, in which CNTs formed by growth method are used as emitters. Generally, since it is easier to form emitters using a paste mixture than by a growth method, the former method is preferred. Unfortunately, the method of making in Choi ""761 and Lee ""281 has a significantly high failure rate and the resulting devices do not always have superior electrical characteristics.
It is therefore an object of the present invention to provide an improved method of making a field emission device.
It is also an object to provide a method for making a field emission device that results in a field emission device that has superior electron emission characteristics.
It is yet another object of the present invention to provide a method of manufacturing a field emission device that results in a field emission device that uniformly emits light having a high brightness.
It is still an object of the present invention to provide a method of manufacturing a field emission device which prevents a short circuiting between the emission material and the gate, thus forming emitters having excellent electron emission characteristics.
These and other objects can be achieved by a method of manufacturing a field emission device. The method begins with preparing a substrate structure, forming a cathode electrode on the substrate, forming a gate insulating layer on the cathode electrode, the gate insulating layer having holes or perforations that expose portions of the cathode electrode, and a gate electrode on the gate insulating layer, the gate having gate holes or perforations that correspond to the holes in the gate insulating layer. A patterned sacrificial layer is then formed on a surface of the structure except on areas of the cathode that are exposed. Then an isolation layer is formed on the entire structure including on the patterned sacrificial layer and on exposed portions of the cathode. An organic emission layer is then formed on the entire structure over the isolation layer. The organic emission layer and the isolation layers are patterned during lift off of the patterned sacrificial layer. A solvent dissolves the patterned sacrificial layer and portions of the isolation layer and the emission layer over the patterned sacrificial layer are washed away during the lift off. The resulting patterned emission layer takes the form of emitters, whose pattern is dictated by the patterned sacrificial layer. Then, the emitters are applied with electricity and fired to rid of any isolation material between the remaining organic emission material and the cathode electrode.